미생물 성장 특성에 기초한 독립영양탈질의 화학양론식 연구

이수원,김규동,최영균,김동한,정태학 대한상하수도학회 2004 상하수도학회지 Vol.18 No.2

It is necessary to supply external carbon source for enhancement of biological nitrogen removal from domestic wastewater with low influent C/N ratio. Sulfide was chosen as a cost effective electron donor and reaction stoichiometry for autotrophic denitrification was investigated by conducting bench-scale experiments in this study. Higher sulfur to nitrogen (S/N) ratio than the calculated value from theoretical reaction stoichiometry was required when the anoxic reactor was operated at open condition because dissolved oxygen introduced by surface aeration reacted with sulfide with ease. In addition, higher sulfate production and lower yield of microorganism could be observed under the same condition. It was possible to obtain reliable reaction stoichiometry for autotrophic denitrification by establishing pure anoxic condition. Linear relationship between bacterial growth and consumption of nitrate, sulfide, alkalinity, and sulfate production enabled to derive a relatively correct reaction stoichiometry for autotrophic denitrification when sulfide was used as an electron donor.

직접인장 모드에 의한 신·구콘크리트의 부착강도 특성 분석

이봉학,홍창우,김동호,김성환 강원대학교 부설 석재복합신소재 제품연구센터 2002 석재연 논문집 Vol.7 No.-

본 연구에서는 부착 특성평가를 위하여 코어깊이, 덧씌우기 두께, 기존 콘크리트와 덧씌우기 재료의 탄성계수비, Steel Disk의 두께를 변화하여 유한요소해석을 실시하였다. 이때 부착면에 발생한 응력의 특성을 비교하여 응력집중계수를 산출하여 최적의 직접인장시험 기준을 마련하고자 하였다. 제안된 실험 방법의 검증을 위하여 보통콘크리트와 초속경 라텍스 개질 콘크리트를 사용하여 실내실험을 실시하였다. 이 두 재료의 부착강도특성을 분석하기 위해서 보통콘크리트와 라텍스 개질 콘크리트로 구성된 복합콘크리트 슬래브를 제작하여 직접인발실험(Pull-out test)을 실시하였다. 주요 실험변수로써 코어직경, 코어깊이, 부착면의 수분상태에 따른 초속경 라텍스 개질 콘크리트의 부착강도 특성을 분석하였다. Significant improvements in the bond strength between new and existing concretes can be achieved through the modification of the new concrete by latex modification. But, no test method has been adopted as a standard to measure the bond strength between the concretes used to repair and the substrate being repaired. The performance of old and the new concretes construction depends upon bond strength between old and the new concretes. Current adhesive strength measurement method ignores the effect of stress concentration by shape of specimens. Therefore, this research calculated stress concentration coefficient using finite element analysis and direction tensile strength test (pull-off test). The result showed that the minimum required core depth was 2.5㎝. Elastic modulus and overlay thickness did not affect to stress concentration.

유한요소해석과 실험검증을 통한 콘크리트 직접인발 시험방법 개발

이봉학,김동호,김성환,김현오 강원대학교 부설 석재복합신소재 제품연구센터 2003 석재연 논문집 Vol.8 No.-

시험편 형상에 의해 발생되는 불규칙한 응력 분포의 하나인 응력집중은 정확한 부착강도 측정을 위하여 최소화해야한다. 이 논문은 pull-off 시험에 영향을 주는 주요 인자들인, 코어 천공 깊이, 강판의 강성, 탄성계수 비, 덧씌우기 두께에 대하여 논의 하고자 한다. 콘크리트 계면에서 위의 변수에 의한 응력 집중의 영향을 평가하기 위하여 유한 요소 해석을 수행하였고, 유한 요소 해석을 통해, 현장 적용을 위한 뛰어난 콘크리트 pull-off 부착강도 시험 방법을 제안하였다. 유한 요소 해석으로부터 제안된 방법은 실험을 통해 검증하였다. 또한 pull-off 시험 방법과 휨 시험 방법과 니플 파이프 직접 인장 시험 방법에 의한 실험을 실시하고 그 결과를 비교하였을 때 표준편차의 관점에서 좋은 결과를 보임을 알 수 있었다. The stress concentration, which is one of non-uniform stress distribution and arises from specimen geometry, should be minimized in order to measure the bond strength correctly. This study discusses the main relevant issues effecting to core pull-off test, namely, core drilling depth stiffness of steel disk, modulus ratio, overlay thickness and length of between cores and edges. Finite element analysis is carried out in order to investigate the effects of those above into the stress concentration at concrete interface. From a series of finite element analysis, a fine concrete pull-off bond strength test method is proposed for field application. The proposed method from finite element analysis is evaluated from a series of experiments. The test results show that the repeatability of the core pull off test are comparable and relatively good in terms of standard deviation, compared from those of flexural beam test method and nipple pipe direct tensile test method.

강섬유 보강 콘크리트의 인장강성 및 피로파괴특성

이봉학,윤경구,홍창우,김동호 강원대학교 부설 석재복합신소재 제품연구센터 2000 석재연 논문집 Vol.5 No.-

콘크리트의 취성적 성질을 개선하고 부재의 인성을 증가시킨 강섬유보강 콘크리트는 건설분야에 활용할 가치가 크다. 그러나 설계규준이나 해석방법이 정비되지 못한 현 실정에서 거동 특성을 규명하고 이에 유효하고 타당한 해석모델을 제시하는 것이 요구된다. 본 논문에서는 강섬유보강 콘크리트의 강도특성실험, 직접인장실험 및 피로실험을 수행하여 이에 대한 역학적 특성을 고찰하고 거동특성을 규명함으로서 설계와 해석의 기초 자료로 활용하고자 하였다. This study is conducted on the test to find tension stiffening, flexural fatigue characteristics and mechanical properties of steel fiber reinforced concrete. Experimental investigation is examined accord to hooked type fiber contents(0, 0.4 , 0.7, 1.0%), fiber aspect ratio(60.83). The principal results obtain through this study are as follows; steel fiber reinforced concrete is increased completely tensile & flex strength properties compared with normal concrete. The tension stiffening and fatigue life tend considerably increase with fiber contents, fiber aspect ratio.

위암 환자의 복강내 투여를 위한 Activated Charcoal-Alginate Bead 제형으로부터 Mitomycin C의 용출 거동

이진호,최선웅,서중기,김동민,정경수,오정연,김진향,노승무,민병무,김용백,김창식,박근성,강대영,송규상,양준묵,조준식,정현용,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

Locoregional recurrence is the most common type of recurrence in surgical operation of gastric adenocarcinoma, and peritoneal dissemination is one of the most difficult problems in advanced gastric adenocarcinoma treatment. Because the peritoneal cavity is the most common site of the first recurrence after gastric cancer resection, intraperitoneal chemotherapy seems a logical choice for cancer chemotherapy. In this study, Mitomycin C (MMC)-activated charcoal (CH)-alginate (ALG) beads were prepared by the mixtures of CH particles adsorbed with MMC as an anti-cancer drug and aqueous alginate solution. The alginate is recognized as biodegradable, nontoxic, and biocompatible. The release of MMC from the beads in 0.1 M Tris buffer was stable and continuous until about 1 week. The MMC-CH-ALG beads can be applied in the peritoneal cavity for intraperitoneal chemotherapy since they provide a good adhesiveness on the tissue and controlled release pattern of the drugs.

지방척수수막류 14례의 임상 분석 : Clinical Analysis of 14 Cases

이정호,신규만,김명현,송준혁,박향권,김성학,박동빈 대한신경외과학회 1996 Journal of Korean neurosurgical society Vol.25 No.6

Lipomyelomeningocele is the most common malformation leading to spinal cord tethering. Nonetheless, these lesion continues to pose a challenge in patient management. The purpose of this study was to identify the clinical feature, candidate for surgical repair, and outcome of lipomyelomeningocele in young children and adults. We studied the magnetic resonance images and/or lumbar myelo-CT of lipomyelomeningocele performed between January 1987 and September 1995 at our institutions and reviewed the pertinent medical records and radiologic studies to determine clinical feature, surgical candidate, and outcomes of these patients. Of the 14 cases(11 female and 3 males) studied, the most common factor that caused these patients to seek help was the cosmetic effect of the mass on their back, followed by urinary incontinence, and weakness of lower extremities. The patients' age ranged from 2 months to 21 years(mean, 5.0 years). All the patients underwent immediate surgical management that consisted of removal of lipoma, untethering of the cord, and complete dural sac repair. Follow up for these patients ranged from 6 to 82 months(median, 54 mo). None of the patients that underwent surgical correction before the emergence of neurological deficit had ever developed neurological deficits at the end of the follow up. However a few of the patients, despite presented with neurological deficits or urinary incontinence at the time of surgery, improved significantly. In conclusion, early detection and prophylactic surgery is imperative to prevent permanent neurological deficits and urinary dysfunction.

ATM 망에서 적응적 분할 버퍼 공유기법에 관한 연구

이용학,정용성 濟州大學校 産業技術硏究所 1998 산업기술연구소논문집 Vol.9 No.1

In this paper. The APBS(Adaptive Partition Buffer Sharing)scheme in ATM network were performance evaluation. we assume that each priority cells are generated with arrival rates λ_(H). λ_(M) and λ_(L) according to Poisson distribution and service is processed with mean service rate μ . The results, APBS scheme can not only guarantee the quality of services for high priority cells but also adaptively service low priority cells according to current buffer state. Therefore, our APBS scheme can improve the quality of service and efficiently utilize the resource of networks.

특발성 과호산구 증후군 환자의 치료 도중 발생한 간혈종 1례

이영태,김동기,박지훈,김윤정,김기향,박보민,권민정,김애란,이원식,주영돈,손창학 白中央醫療院 2005 仁濟醫學 Vol.26 No.1

Idiopathic hypereosinophilic syndrome is characterized by marked elevation of eosinophil count ( >1,500/㎣) in peripheral blood without explaining etiology. It shows tissue involvement in many organs such as liver, G-I tract, myocar dium, lung, skin, kidney and nerve. Some case of hypereosinophilic syndrome with hepatic involvement have been reported, but not much. We have recently experienced a case with idiopathic hypereosinophilic syndrome of a 40 year old man who presented with RUQ pain. By abdominal CT, ill- defined subcapsular hematoma was detected. Liver biopsy showed eosinophilic infiltration within the portal tract and sinusoid. Drain procedure and corticosteroid adminiiatbrought marked improvement of clinical manifestation, hematologic abnormality and radiologic abnormality.

鐵筋콘크리트 보의 附着擧動에 관한 硏究

이주형,이봉학,홍창우,김동호 江原大學校 産業技術硏究所 1998 産業技術硏究 Vol.18 No.-

Cracking is considered to be one of the important factors in determining the durability of reinforced concrete structures. When the bending stress exceeds the modulus of rupture of the concrete, cracking fom along the length of members. The total load is transferred across these cracks by the reinforcement, but the concrete between craks is still capable of carrying stresses due to the bond between steel and concrete. This phenomenon is called the tension stifening effect. The tension stiffening effect is affected by many variables, such as the bond stress, strength of concrete, interrocking of aggregate, type of steel, and dowel action of steel. Also, this tension stifening effect is usually quite significant in beams under service loading, and must be taken into account in the calculation of deflection and crack widths. In this study, the experiment was carried out on types of specimen, strength of concrete, and steel ratio and finite element analysis were compared in terms of load-deflection relationship, crack pattern.

소포제 종류 및 혼입률에 따른 초속경 라텍스개질 모르타르의 역학적 특성

이봉학,홍창우,이주형,김동호 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid-setting cement) by choosing the best antifoam agent type. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as a basic experiments for RSLMC with the main experimental variables such as antifiamer types (A, B, C, D), antifoamer contents(0, 1, 2, 3%), and latex contents(10, 15%). Air content test and compressive strength tests were carried out to measure the improved properties of RSLMM. SEM analysis, also, was carried to observe the formation of latex film. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing an antifoam agent by 1%. This made the strength enhanced and the workability be within the purposed. The best properties of compressive strengths was obtained at latex content of 15% and D antifoam agent of 1%. compressive strength increased about 32.6%. The analysis of SEM results no difference in a formation of later film.